Conventional J-channels are formed by extrusion of filled polymer compounds having uniform composition and a single durometer (hardness) rating. These J-channels perform well around structures having substantially straight sides. However, usage of the prior art J-channels around curved openings or curved structures (e.g., round or half round windows or round louvers) is difficult. Fitting of conventional J-channels around such structures requires cutting of the rear legs or both the front and rear legs followed by patching with caulking compound or other similar material to avoid gaps.
Garries et al U.S. Pat. No. 4,920,709 discloses a J-channel member for accommodating junctures between siding and radiused openings. The patented member includes a bottom wall, a front leg, and a back leg. The back leg is made of a relatively rigid plastic material and has vertically extending through slits to permit bending of the bottom wall around a radiused opening.
It is a principal objective of the present invention to provide a flexible J-channel that is readily bent around curved openings and curved building structures.
A related objective of the invention is to provide a J-channel that is coextruded as a one-piece structure with a base wall of relatively rigid polymer composition and front and rear walls of relatively flexible polymer composition.
Another objective of the invention is to provide a J-channel having a rear wall that is uninterrupted by through slits which might detract from strength and weather resistance.
Additional objects and advantages of the present invention will become apparent to persons skilled in the art from the following specification and claims.